cpu/amd/pi: Use alloc_cbmem() only in ramstage

Without this change the builder would fail with the complaint
that there was a global static variable in romstage. alloc_cbmem()
is only called in ramstage. The alternative was to add
*/cpu/amd/pi/*.romstage.o to the list of illegal_globals
EXCLUDE_FILEs in arch/x86/init/romstage.ld.

TEST: Booted the amd/lamar board.

Change-Id: I5167910ff790a3152a4ad8e5af0a4a3b17894f0f
Signed-off-by: Dave Frodin <dave.frodin@se-eng.com>
Reviewed-on: http://review.coreboot.org/8256
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>
diff --git a/src/cpu/amd/pi/heapmanager.c b/src/cpu/amd/pi/heapmanager.c
index 22c72fb..e33b29f 100644
--- a/src/cpu/amd/pi/heapmanager.c
+++ b/src/cpu/amd/pi/heapmanager.c
@@ -28,7 +28,7 @@
 	memset(BiosManagerPtr, 0, BIOS_HEAP_SIZE);
 }
 
-#if IS_ENABLED(CONFIG_NORTHBRIDGE_AMD_PI_00630F01)
+#if IS_ENABLED(CONFIG_NORTHBRIDGE_AMD_PI_00630F01) && !defined(__PRE_RAM__)
 
 #define AGESA_RUNTIME_SIZE 4096
 
@@ -74,7 +74,7 @@
 	AllocParams = ((AGESA_BUFFER_PARAMS *) ConfigPtr);
 	AllocParams->BufferPointer = NULL;
 
-#if IS_ENABLED(CONFIG_NORTHBRIDGE_AMD_PI_00630F01)
+#if IS_ENABLED(CONFIG_NORTHBRIDGE_AMD_PI_00630F01) && !defined(__PRE_RAM__)
 	/* if the allocation is for runtime use simple CBMEM data */
 	if (Data == HEAP_CALLOUT_RUNTIME)
 		return alloc_cbmem(AllocParams);